Steam generator and nuclear reactor comprising same

Abstract

This steam generator comprises: a case through which a nuclear reactor coolant flows; a heat transfer tube including a plurality of heat transfer tube passages through which feedwater moves; a feedwater header connected to the heat transfer tube and for supplying the feedwater; a steam header in which the feedwater supplied from the feedwater header is phase-changed into main steam and from which the main steam is discharged; an orifice disposed inside the feedwater header and including a plurality of orifice passages in communication with the heat transfer tube passages; and a driving means moving a position of the orifice relative to the heat transfer tube in order to adjust a pressure loss of the feedwater flowing into the heat transfer tube, wherein the driving means includes a bellows tube that expands or contracts so that the orifice moves, and a compressible fluid filled inside the bellows tube to cause expansion or contraction of the bellows tube.

Description

Steam generator and nuclear reactor including the same

[0001] The present invention relates to a steam generator and a nuclear reactor including the same.

[0002] Generally, nuclear reactors are classified into separated reactors, in which major equipment (steam generators, pressurizers, etc.) is installed outside the reactor vessel (e.g., domestic pressurized light water reactors, Japanese boiling light water reactors), and integrated reactors, in which major equipment is installed inside the reactor vessel.

[0003] Integrated reactors have the advantage of fundamentally eliminating major loss-of-coolant accidents because key equipment is housed inside the reactor vessel, but they have the disadvantage of having a larger reactor vessel relative to capacity compared to separated reactors because steam generators, pressurizers, and pumps are installed inside the vessel.

[0004] Recently, small modular reactors (SMRs) are being developed as integrated reactors. In this type of reactor, a reactor vessel containing a core, a steam generator, and pumps is provided, and the cooling water contained within the reactor vessel is circulated by pumps and flows to the core and steam generator to generate electricity.

[0005] Here, in the steam generator, when the supplied feed water flows in the form of supercooled water and passes through the heat transfer tubes, it receives heat from the cooling water of the primary system moving outside the heat transfer tubes and can boil at a specific point. In other words, as the feed water passes through the heat transfer tubes, it exchanges heat with the heated cooling water of the primary system, undergoes a phase change from liquid to gas, is converted into complete steam, and finally becomes superheated steam, which moves along the secondary system to the turbine.

[0006] These conventional steam generators can cause instability in the flow of supercooled feedwater during reactor operation, particularly under low-power operating conditions. Therefore, to resolve the instability of feedwater flow, conventional steam generators solve the problem by placing an orifice at the point where the feedwater flows.

[0007] However, orifices installed in conventional steam generators have the problem of potentially increasing reactor operating costs by unnecessarily causing high pressure losses under high-power operating conditions.

[0008] Embodiments of the present invention were invented against the background described above and aim to provide a steam generator capable of suppressing feedwater flow instability that may occur under low-power operating conditions of the reactor, and high pressure loss of feedwater that may occur under high-power operating conditions of the reactor, and a reactor including the same.

[0009] A steam generator according to one aspect of the present invention comprises: a case through which a reactor coolant passes; a heat transfer tube disposed inside the case and comprising a plurality of heat transfer tube passages through which feedwater travels; a feedwater header communicating with the heat transfer tube and for supplying the feedwater to the heat transfer tube; a steam header connected to the heat transfer tube so that the feedwater of the heat transfer tube is heated and discharged as steam; an orifice disposed inside the feedwater header and comprising a plurality of orifice passages that selectively communicate with the heat transfer tube passages; and a driving means for moving the position of the orifice relative to the heat transfer tube to control the pressure of the feedwater flowing into the heat transfer tube; wherein the driving means comprises a bellows tube that expands or contracts to move the orifice, and a compressible fluid filled inside the bellows tube to expand or contract the bellows tube.

[0010] In addition, the compressible fluid may contract or expand due to the temperature of the water supplied through the water supply header.

[0011] In addition, the bellows tube can move the orifice in a direction perpendicular to the direction in which the orifice passage extends so that the size of the cross-sectional area in which the heat transfer tube passage and the orifice passage communicate with each other can be varied.

[0012] Additionally, the orifice may be moved by the driving means to be positioned at a first communication position where the cross-sectional area communicating between the heat transfer tube channel and the orifice channel is largest, or at a second communication position where the cross-sectional area communicating between the heat transfer tube channel and the orifice channel is smallest.

[0013] Additionally, it may further include a driving auxiliary means positioned on the opposite side of the position where the bellows tube is arranged so that when the orifice placed at the second communication position is moved to the first communication position by the driving means, a pressurizing force is applied to the orifice.

[0014] In addition, the orifice passage includes a first passage, a second passage, and a third passage having different diameters, and the first passage, the second passage, and the third passage may be arranged according to the direction in which the orifice moves so that the size of the cross-sectional area communicating with the heat transfer tube passage can be varied when the orifice moves.

[0015] In addition, the orifice channel may have a shape in which the area decreases in the direction in which the orifice moves, so that the size of the cross-sectional area communicating with the heat transfer tube channel can be varied when the orifice moves.

[0016] Additionally, the system further includes a main steam pipe connected from the steam header to the bellows pipe, and the bellows pipe can contract and expand by the pressure of the main steam supplied through the main steam pipe.

[0017] Additionally, the orifice may further include a plurality of control pins arranged to be spaced apart from the heat transfer tube passage, having a shape that protrudes in the direction in which the orifice passage extends, and the bellows tube may reciprocate the orifice toward the heat transfer tube passage so that the flow rate of the water supply can be varied as the spacing between the control pin and the heat transfer tube passage increases or decreases.

[0018] Additionally, the orifice may further include a plurality of control pins arranged to be spaced apart from the heat transfer tube passage, having a shape that protrudes in the direction in which the orifice passage extends, and the orifice has one surface facing the heat transfer tube passage and another surface opposite to the one surface on which the bellows tube is arranged, and the bellows tube can reciprocate the orifice toward the heat transfer tube passage so that the flow rate of the water supply can be varied as the spacing between the control pin and the heat transfer tube passage increases or decreases.

[0019] Additionally, the orifice may include an orifice body; and a plurality of fluid pin portions that reciprocate in the direction in which the orifice flow path extends, and the bellows tube may be disposed between the orifice body and the fluid pin portions to reciprocate the fluid pin portions in the direction in which the orifice flow path extends.

[0020] Additionally, the plurality of heat transfer tube channels may include a first heat transfer channel having a predetermined length, a second heat transfer channel having a longer length than the first heat transfer channel, and a third heat transfer channel having a longer length than the second heat transfer channel, and when the plurality of orifice channels are selectively connected to the plurality of heat transfer tube channels, the cross-sectional area communicating with the plurality of heat transfer tube channels may be arranged to be different for each.

[0021] Additionally, the driving means may further include a driving auxiliary means that pressurizes the orifice in a direction opposite to the direction in which the driving means moves the orifice, and the orifice may be positioned between the driving means and the driving auxiliary means.

[0022] In addition, the above driving assist means may be formed as a corrugated tube in a near-vacuum state.

[0023] In addition, the above driving assist means may include a corrugated tube in a near-vacuum state.

[0024] In addition, it may include a spring having elasticity or a corrugated tube containing a spring inside.

[0025] A reactor according to another aspect of the present invention comprises: a reactor vessel containing a coolant; a core that causes nuclear fission inside the reactor vessel; and a steam generator that generates steam through heat exchange of the coolant; the steam generator comprises: a case through which the reactor coolant passes; a heat transfer tube including a plurality of heat transfer tube passages through which feedwater travels; a feedwater header connected to the heat transfer tube and for supplying the feedwater; a steam header through which the feedwater supplied from the feedwater header undergoes phase transformation into main steam and is discharged; an orifice disposed inside the feedwater header and including a plurality of orifice passages communicating with the heat transfer tube passages; and a driving means for moving the position of the orifice relative to the heat transfer tube to regulate the pressure of the feedwater flowing into the heat transfer tube; the driving means comprises a bellows tube that expands or contracts to move the orifice, and a compressible fluid filled inside the bellows tube to expand or contract.

[0026] According to embodiments of the present invention, by controlling to suppress flow instability of the feedwater that may occur under low-power operating conditions of the reactor and high pressure loss of the feedwater that may occur under high-power operating conditions of the reactor, the thermohydraulic load of steam generation is alleviated, and the structural safety and integrity of the steam generator can be ensured.

[0027] FIG. 1 is a partial cross-sectional view showing a nuclear reactor according to a first embodiment of the present invention.

[0028] Figure 2 is a partial perspective cross-sectional view showing the steam generator of Figure 1.

[0029] Figures 3a and 3b are cross-sectional views showing the internal structure of the water supply header of Figure 2.

[0030] Figure 4 is an enlarged view of section 'A' of Figure 3.

[0031] FIG. 5 is a diagram showing the state in which the first orifice flow path has moved to a position having a first pressure loss coefficient.

[0032] FIG. 6 is a diagram showing the state in which the first orifice flow path has moved to a position having a second pressure loss coefficient.

[0033] Figure 7 is a diagram showing the state in which the first orifice flow path has moved to a position having a third pressure loss coefficient.

[0034] Figure 8 is a diagram illustrating the cross-sectional area in which the first orifice channel and the heat transfer tube channel are in communication.

[0035] FIG. 9 is a diagram showing the state in which the second orifice flow path has moved to a position having the first pressure loss coefficient.

[0036] FIG. 10 is a diagram showing the state in which the second orifice flow path has moved to a position having a second pressure loss coefficient.

[0037] FIG. 11 is a diagram showing the state in which the second orifice flow path has moved to a position having a third pressure loss coefficient.

[0038] FIG. 12 is a diagram showing the state in which the third orifice flow path has moved to a position having a first pressure loss coefficient.

[0039] FIG. 13 is a diagram showing the state in which the third orifice flow path has moved to a position having a second pressure loss coefficient.

[0040] FIG. 14 is a diagram showing the state in which the third orifice flow path has moved to a position having a third pressure loss coefficient.

[0041] FIG. 15 is a diagram showing a drive driven by the pressure of the main steam according to the second embodiment of the present invention.

[0042] FIG. 16 is a diagram showing the operation of an orifice according to a third embodiment of the present invention.

[0043] Figure 17 is a diagram showing the operation of the control pin by enlarging "B" of 16.

[0044] FIG. 18 is a diagram showing the operation of an orifice according to a fourth embodiment of the present invention.

[0045] FIG. 19 is a diagram showing the operation of an orifice according to a fifth embodiment of the present invention.

[0046] FIG. 20 is a diagram showing the operation of the movable pin by enlarging "C" of FIG. 19.

[0047] Hereinafter, specific embodiments for implementing the technical concept of the present invention will be described in detail with reference to the drawings.

[0048] In addition, in describing the present invention, if it is determined that a detailed description of related known components or functions may obscure the essence of the invention, such detailed description is omitted.

[0049] Furthermore, when it is mentioned that one component is 'connected,' 'supported,' 'supplied,' or 'transmitted' to another component, it should be understood that while the connection, support, supply, or transmission may be direct to that other component, there may also be other components present in between.

[0050] The terms used in this specification are used merely to describe specific embodiments and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise.

[0051] Furthermore, it should be noted in advance that expressions such as "upper side," "lower side," and "side" in this specification are described based on the drawings, and may be expressed differently if the orientation of the object changes. For the same reason, some components in the attached drawings may be exaggerated, omitted, or schematically depicted, and the size of each component does not entirely reflect its actual size.

[0052] Additionally, terms including ordinal numbers, such as first, second, etc., may be used to describe various components, but such components are not limited by such terms. These terms are used solely for the purpose of distinguishing one component from another.

[0053] The meaning of "comprising" as used in the specification is to specify certain characteristics, regions, integers, steps, actions, elements, and / or components, and does not exclude the existence or addition of other specific characteristics, regions, integers, steps, actions, elements, components, and / or groups.

[0054] Hereinafter, a specific configuration of a steam generator according to the first embodiment of the present invention and a reactor including the same will be described with reference to the drawings.

[0055] Referring to FIG. 1, a reactor (1) according to the first embodiment of the present invention is a power generation device that generates heat through a core that causes nuclear fission and generates steam and electricity through the generated heat. As an example, the reactor (1) in the present invention may be a Small Modular Reactor (SMR). Such a reactor (1) may include a reactor vessel (10), a core (20), and a steam generator (30).

[0056] The reactor vessel (10) can accommodate a core (20) and a steam generator (30). The reactor vessel (10) can accommodate a reactor coolant (C1) that is heated through the core (20) and exchanges heat with the steam generator (30). The reactor vessel (10) can be provided in the form of a sealed tank to prevent radioactive fissile material from leaking out.

[0057] The core (20) can be placed inside the reactor vessel (10) to generate nuclear fission. The core (20) can be placed inside the reactor vessel (10). The core (20) can generate nuclear fission to heat the reactor coolant (C1) circulating inside the reactor vessel (10).

[0058] Referring to FIGS. 2 through 4, a steam generator (30) can generate steam through heat exchange with a reactor coolant (C1) heated by a core (20). The steam generator (30) can be placed on the circulation path of the reactor coolant (C1) circulating inside the reactor vessel (10). The steam generator (30) may be provided with a primary path through which the reactor coolant (C1) of the reactor vessel (10) travels, and a secondary path through which feedwater undergoing a phase change into steam travels. Such a steam generator (30) may be connected to a turbine that generates electricity. Such a steam generator (30) may include a case (100), a heat transfer tube (200), a feedwater header (300), a steam header (400), an orifice (500), a driving means (600), and a driving auxiliary means (700).

[0059] The case (100) can accommodate a heat transfer tube (200) inside. The case (100) can be open at the top and bottom to allow the reactor coolant (C1) to pass through. The case (100) can be connected to a water supply pipe that supplies water (C) and a steam discharge pipe connected to a turbine. The case (100) can be a tank that provides space inside.

[0060] The heat transfer tube (200) may be placed inside the case (100). The heat transfer tube (200) may be a passage through which feedwater (C) travels. The heat transfer tube (200) may be wound in a spiral shape inside the case (100). The heat transfer tube (200) may be a conduit that moves feedwater (C) supplied through the feedwater header (300) to the steam header (400). Multiple heat transfer tubes (200) may be provided. The heat transfer tube (200) may be a space where the supplied feedwater (C) boils into steam while exchanging heat with the reactor coolant (C1). When the heat transfer tube (200) is wound in a spiral shape inside the case (100), the length of the heat transfer tube (200) wound on the inner side of the case (100) (the part adjacent to the spiral central axis) and the length of the heat transfer tube (200) wound on the outer side (the part spaced apart from the spiral central axis) may be different from each other. Such a heat transfer tube (200) may include a heat transfer tube channel (210).

[0061] The heat transfer tube passage (210) may be a passage through which the feed water (C) travels. The heat transfer tube passage (210) may be connected longitudinally within the interior of the heat transfer tube (200). The heat transfer tube passage (210) may be a passage through which the feed water (C) travels and a space that boils while undergoing a phase change into main steam (S). The heat transfer tube passage (210) may be provided in multiple numbers. Such heat transfer tube passages (210) may include a first heat transfer passage (211), a second heat transfer passage (212), and a third heat transfer passage (213).

[0062] The first heat transfer channel (211) may be positioned at the innermost part inside the case (100). The first heat transfer channel (211) may have the shortest length compared to the second heat transfer channel (212) and the third heat transfer channel (213).

[0063] The second heat transfer channel (212) may be positioned inside the case (100) between the first heat transfer channel (211) and the third heat transfer channel (213). The second heat transfer channel (212) may have an intermediate length compared to the first heat transfer channel (211) and the third heat transfer channel (213).

[0064] The third heat transfer channel (213) may be positioned at the outermost part inside the case (100). The third heat transfer channel (213) may have the longest length compared to the first heat transfer channel (211) and the second heat transfer channel (212).

[0065] The water supply header (300) may be an inlet for supplying water (C) to the heat transfer tube (200). The water supply header (300) may be connected to the end of the heat transfer tube (200). The water supply header (300) may be connected to the outer surface of the case (100). For example, the water supply header (300) may include a pipe connected to the water supply pipe and a connection part connected to the heat transfer tube (200).

[0066] The steam header (400) may be an outlet through which the main steam (S) boiled in the heat transfer tube (200) is discharged. The steam header (400) may be connected to the opposite end of the heat transfer tube (200) to which the water supply header (300) is connected. The steam header (400) may be connected to the outer surface of the case (100). For example, the steam header (400) may include a pipe to which the steam discharge pipe is connected and a connection part to which the heat transfer tube (200) is connected.

[0067] The orifice (500) may be positioned inside the water supply header (300). The orifice (500) may be moved by a driving means (600) so that the pressure of the water supply (C) is regulated. In other words, the orifice (500) may be moved inside the water supply header (300) by driving the driving means (600). The orifice (500) may be positioned adjacent to the heat transfer tube (200) connected to the water supply header (300). The orifice (500) may be moved by the driving means (600) so as to be placed at a first communication position where the area of ​​communication between the heat transfer tube channel (210) and the orifice channel (520), which will be described later, is the largest, or at a second communication position where the area of ​​communication between the heat transfer tube channel (210) and the orifice channel (520) is the smallest. The orifice (500) may include an orifice body (510) and an orifice flow path (520).

[0068] The orifice body (510) may be the body of the orifice (500). The orifice body (510) may be fixed at a predetermined position by a support protrusion (not shown) provided inside the water supply header (300). A bellows tube (610) may be seated on one side of the orifice body (510). The orifice body (510) may be provided with a pipe-shaped seating portion to allow the bellows tube (610) to be seated.

[0069] The orifice passage (520) may be a passage through which the water supply (C) passes through the orifice (500). The orifice passage (520) may be arranged in communication with the heat transfer tube passage (210). When the orifice passage (520) is moved by the driving means (600), the area communicating with the heat transfer tube passage (210) may be varied. The orifice passage (520) may be provided in multiple numbers. When the multiple orifice passages (520) are selectively communicated with the multiple heat transfer tube passages (210), they may be arranged such that the area communicating with the multiple heat transfer tube passages (210) is different as D1, D2, and D3, respectively. In other words, the multiple orifice passages (520) may be arranged at a different spacing than the spacing at which the multiple heat transfer tube passages (210) are arranged.

[0070] For example, FIGS. 5 to 8 illustrate a first example of an orifice (500), wherein the cross-sectional area communicating from the first heat transfer channel (211) to the third heat transfer channel (213) may differ depending on the position of the multiple orifice channels (520). As shown in FIG. 5, when the openings of the multiple orifice channels (520) are positioned such that they all encompass the openings of the multiple heat transfer channels (210) when viewed from the direction of extension of the heat transfer tube channel (210), the water supply (C) can flow with a low pressure loss coefficient. Additionally, as shown in FIG. 6, when the orifice (500) is moved upward so that when viewed from the extension direction of the heat transfer tube passage (210), the openings of the multiple orifice passages (520) partially include the openings of the multiple heat transfer tube passages (210), the water supply (C) can flow with an intermediate pressure loss coefficient. Additionally, as shown in FIG. 7, when the orifice (500) is moved further upward so that when viewed from the extension direction of the heat transfer tube passage (210), the openings of the multiple orifice passages (520) partially include the openings of the multiple heat transfer tube passages (210), the water supply (C) can flow with a high pressure loss coefficient.

[0071] FIGS. 9 to 11 illustrate a second example of an orifice (500), wherein the orifice passage (520) may have a shape in which the area of ​​the orifice (500) decreases in the direction in which the orifice (500) moves so that the size of the area communicating with the heat transfer tube passage (210) can be varied when the orifice (500) moves.

[0072] FIGS. 12 to 14 illustrate a third example of an orifice (500), wherein the orifice flow path (520) may be formed into a plurality of flow paths in which the area of ​​communication with the heat transfer tube flow path (210) decreases in the direction in which the orifice (500) moves, so that the size of the area communicating with the orifice (500) when the orifice (500) moves may be variable. Such an orifice flow path (520) may include a first flow path (521), a second flow path (522), and a third flow path (523).

[0073] The first flow path (521) can provide a passage connecting the orifice (500) and the heat transfer tube (200) when supplying water (C) at a predetermined pressure. The first flow path (521) may have an inner diameter equal to or larger than that of the heat transfer tube flow path (210). The first flow path (521) may have the largest inner diameter compared to the second flow path (522) and the third flow path (523). The first flow path (521) can flow water (C) with the lowest pressure loss when connected to the heat transfer tube flow path (210).

[0074] The second flow path (522) can provide a passage connecting the orifice (500) and the heat transfer tube (200) when supplying water (C) at a predetermined pressure. The second flow path (522) may have a smaller inner diameter than the first flow path (521). The second flow path (522) may have an intermediate inner diameter compared to the first flow path (521) and the third flow path (523). In other words, the second flow path (522) may have an inner diameter smaller than the first flow path (521) and larger than the third flow path (523). The second flow path (522) can flow water (C) with an intermediate pressure loss when connected to the heat transfer tube flow path (210).

[0075] The third flow path (523) can provide a passage connecting the orifice (500) and the heat transfer tube (200) when supplying water (C) at a predetermined pressure. The third flow path (523) may have a smaller inner diameter than the first flow path (521) and the second flow path (523). The third flow path (523) can flow water (C) while having the highest pressure loss when connected to the heat transfer tube flow path (210).

[0076] The driving means (600) can move the orifice (500) in one direction. The driving means (600) can move the position of the orifice (500) relative to the heat transfer tube (200) to regulate the pressure of the water supply (C) flowing into the heat transfer tube (200). The driving means (600) can be connected to the orifice (500). Such driving means (600) may include a bellows tube (610) and a compressible fluid (620).

[0077] The bellows tube (610) may be a corrugated tube that expands or contracts to move the orifice (500). The bellows tube (610) may be connected to the orifice (500). Multiple bellows tubes (610) may be provided. The bellows tube (610) may move the orifice (500) in a direction perpendicular to the direction in which the orifice passage (520) extends so that the size of the area in which the heat transfer tube passage (210) and the orifice passage (520) communicate with each other may be varied.

[0078] A compressible fluid (620) can be filled inside the bellows tube (610). The compressible fluid (620) can expand or contract depending on the temperature of the water supply (C). In other words, the compressible fluid (620) can expand when heated by the water supply (C) and contract when the temperature of the water supply (C) decreases. Additionally, the inside of the bellows tube (610) can expand or contract depending on the pressure of the main steam (S). That is, the inside of the bellows tube (610) can expand when the pressure of the main steam (S) is higher than the set pressure and contract when it is lower.

[0079] The driving aid (700) can move the orifice (500) in the opposite direction of the driving aid (600). The driving aid (700) can be positioned on the opposite side of the position where the bellows tube (610) is positioned in the orifice body (510). In other words, the orifice body (510) can be positioned between the driving aid (700) and the driving aid (600). For example, as shown in FIGS. 3a and 3b, the driving aid (700) may be provided as a corrugated tube in a near-vacuum state, a spring having elastic force, or a corrugated tube containing a spring inside. The driving aid (700) may be positioned on the opposite side of the position where the bellows tube (610) is placed so that when the orifice (500) placed at the second communication position is moved to the first communication position by the driving aid (600), a pressurizing force is applied to the orifice (500).

[0080] The operation and effects of a steam generator having the configuration described above will be explained below.

[0081] In the steam generator (30) according to the first embodiment of the present invention, supercooled feedwater (C) is supplied to the heat transfer tube (200) through the feedwater header (300), and the supplied feedwater (C) flows and circulates through the heat transfer tube (200) wound spirally inside the case (100). Subsequently, the case (100) passes through the reactor coolant (C1) heated in the reactor vessel (10) to perform heat exchange between the reactor coolant (C1) and the feedwater (C). When heat exchange occurs between the reactor coolant (C1) and the feedwater (C), the feedwater (C) is heated through the heat of the reactor coolant (C1), and a boiling phenomenon proceeds in which it undergoes a phase change into steam. The main steam (S) that has undergone a phase change due to the boiling phenomenon is moved to a turbine to produce electricity.

[0082] Meanwhile, when the water supply (C) supplied through the water supply header (300) flows into the heat transfer tube (200), flow instability generally occurs at low flow rates, whereas if an orifice is installed to stabilize the flow, high pressure loss may occur under high flow rate conditions. To solve this, an orifice (500) capable of varying the flow area of ​​the water supply (C) is placed inside the water supply header (300), and the orifice (500) is moved by driving a driving means (600).

[0083] Through this, when feedwater (C) is supplied to the heat transfer tube (200), the orifice (500) moves so that the flow area between the orifice flow path (520) and the heat transfer tube flow path (210) is varied, thereby enabling the suppression of feedwater flow instability that may occur under low-power operating conditions of the reactor and high pressure loss of feedwater that may occur under high-power operating conditions of the reactor.

[0084] Meanwhile, in addition to this configuration, a second embodiment of the present invention may be presented. Hereinafter, a second embodiment of the present invention will be described with reference to FIG. 15. In describing the second embodiment, the differences when compared with the above-described embodiment will be explained in detail, and the same descriptions will be taken from the above-described embodiment.

[0085] Referring to FIG. 15, the steam generator (30) may further include a main steam pipe (800).

[0086] The main steam pipe (800) can supply the main steam (S) of the steam header (400) into the interior of the bellows pipe (610). The main steam pipe (800) may be a pipe connecting the steam header (400) to the bellows pipe (610). The main steam pipe (800) may include a valve that controls the flow of the main steam (S). By supplying the main steam (S) that applies pressure to the bellows pipe (610), the main steam pipe (800) enables the orifice (500) to be easily moved in one direction.

[0087] In addition, a third embodiment of the present invention may be presented in addition to this configuration. Hereinafter, a third embodiment of the present invention will be described with reference to FIGS. 16 and 17. In describing the third embodiment, the differences when compared with the above-described embodiment will be described in detail, and the same descriptions will be taken from the above-described embodiment.

[0088] Referring to FIGS. 16 and 17, the orifice (500) may further include a plurality of adjustment pins (530).

[0089] A plurality of control pins (530) may have a shape that protrudes in the direction in which the orifice passage (520) extends. A plurality of control pins (530) may be arranged to be spaced apart from the heat transfer tube passage (210). A plurality of control pins (530) may be provided in the same number as the heat transfer tube passage (210). A bellows tube (610) may be placed between the plurality of control pins (530) and connected to the inner surface of the water supply header (300). At this time, the bellows tube (610) may expand or contract depending on the temperature of the water supply (C).

[0090] The orifice (500) can increase or decrease the spacing between the control pins (530) and the heat transfer tube passage (210) and control the flow rate of the water supply (C) by reciprocating in the extending direction of the heat transfer tube passage (210) through the expansion or contraction of the bellows tube (610) placed between the plurality of control pins (530).

[0091] Meanwhile, in addition to this configuration, a fourth embodiment of the present invention may be presented. Hereinafter, a fourth embodiment of the present invention will be described with reference to FIG. 18. In describing the fourth embodiment, the differences when compared with the above-described embodiment will be explained in detail, and the same descriptions will be taken from the above-described embodiment.

[0092] Referring to FIG. 18, the orifice (500) may further include a plurality of adjustment pins (530).

[0093] A plurality of control pins (530) may have a shape that protrudes in the direction in which the orifice passage (520) extends. A plurality of control pins (530) may be arranged to be spaced apart from the heat transfer tube passage (210). A plurality of control pins (530) may be provided in the same number as the heat transfer tube passage (210). A bellows tube (610) may be placed on the other side of the orifice (500), which is the opposite side of the one side facing the heat transfer tube passage (210). Meanwhile, a support plate (P) that supports the bellows tube (610) placed on the other side of the orifice (500) may be provided inside the water supply header (300).

[0094] The orifice (500) reciprocates in the extending direction of the heat transfer tube passage (210) by means of a bellows tube (610) that expands or contracts according to the pressure of the main steam (S) supplied through the main steam pipe (800), thereby increasing or decreasing the spacing between the control pin (530) and the heat transfer tube passage (210) and allowing the flow rate of the water supply (C) to be controlled.

[0095] Meanwhile, in addition to this configuration, a fifth embodiment of the present invention may be presented. Hereinafter, a fifth embodiment of the present invention will be described with reference to FIGS. 19 and FIGS. 20. In describing the fifth embodiment, the differences when compared with the above-described embodiment will be described in detail, and the same descriptions will be taken from the above-described embodiment.

[0096] Referring to FIGS. 19 and 20, the orifice (500) may include an orifice body (510) and a movable pin portion (540).

[0097] The flow pin portion (540) can reciprocate in the direction in which the orifice passage (520) extends. The flow pin portion (540) can be supported or moved by a bellows tube (610) seated on the orifice body (510). The flow pin portion (540) may have a shape that protrudes in the direction in which the orifice passage (520) extends. The flow pin portion (540) may be positioned so as to be spaced apart from the heat transfer tube passage (210). The flow pin portion (540) may be provided in the same number as the heat transfer tube passage (210). The bellows tube (610) may be positioned between the orifice body (510) and the flow pin portion (540).

[0098] The flow fin section (540) is positioned between the orifice body (510) and the flow fin section (540), and by reciprocating in the extending direction of the heat transfer tube passage (210) by means of a bellows tube (610) that expands or contracts according to the pressure of the main steam (S) supplied through the main steam pipe (800), the spacing between the flow fin section (540) and the heat transfer tube passage (210) can be increased or decreased, and the flow rate of the water supply (C) can be controlled.

[0099] Although the embodiments of the present invention have been described above as specific embodiments, they are merely examples and the present invention is not limited thereto, but should be interpreted as having the broadest scope in accordance with the technical concept disclosed in this specification. Those skilled in the art may implement patterns of shapes not specified by combining or substituting the disclosed embodiments, and this also does not deviate from the scope of the present invention. Furthermore, those skilled in the art may easily modify or alter the disclosed embodiments based on this specification, and it is evident that such modifications or alterations also fall within the scope of the rights of the present invention.

Claims

1. A case through which the reactor coolant passes; A plurality of heat transfer tube passages through which water flows, and a heat transfer tube disposed inside the case; A water supply header connected to the above heat transfer tube and for supplying the above water to the above heat transfer tube; A steam header connected to the heat transfer tube so that the feed water of the heat transfer tube is heated and discharged as steam; An orifice comprising a plurality of orifice passages disposed inside the above-mentioned water supply header and optionally communicating with the above-mentioned heat transfer tube passage, and To regulate the pressure of the water supply flowing into the heat transfer tube, it includes a driving means for moving the position of the orifice relative to the heat transfer tube; The above driving means is, A bellows tube that expands or contracts to move the orifice, and a compressible fluid filled inside the bellows tube to expand or contract the bellows tube. Steam generator.

2. In Paragraph 1, The above-mentioned compressible fluid is, Contracting or expanding due to the temperature of the water supplied through the above water supply header, Steam generator.

3. In Paragraph 1, The above bellows tube is, Moving the orifice in a direction perpendicular to the direction in which the orifice passage extends so that the size of the cross-sectional area communicating between the heat transfer tube passage and the orifice passage can be varied, Steam generator.

4. In Paragraph 3, The above orifice is, Moved by the driving means to be placed at a first communication position where the cross-sectional area communicating between the heat transfer tube channel and the orifice channel is largest, or at a second communication position where the cross-sectional area communicating between the heat transfer tube channel and the orifice channel is smallest. Steam generator.

5. In Paragraph 4, A driving auxiliary means further comprising a driving auxiliary means disposed on the opposite side of the position where the bellows tube is disposed, such that when the orifice placed at the second communication position is moved to the first communication position by the driving means, a pressurizing force is applied to the orifice. Steam generator.

6. In Paragraph 3, The above orifice flow path includes a first flow path, a second flow path, and a third flow path having different diameters, and The above first Euro, the above second Euro, and the above third Euro are, When the orifice is moved, the size of the cross-sectional area communicating with the heat transfer tube can be varied, and the orifice is arranged according to the direction in which it is moved. Steam generator.

7. In Paragraph 3, The above orifice flow path is, The orifice has a shape in which the area decreases in the direction in which it moves, so that when the orifice moves, the size of the cross-sectional area communicating with the heat transfer tube passage can be varied. Steam generator.

8. In Paragraph 1, It further includes a main steam pipe connected from the steam header to the bellows pipe, and The above bellows tube is, Contracting and expanding by the pressure of the main steam supplied through the above main steam pipe, Steam generator.

9. In Paragraph 1 The above orifice has a shape that protrudes in the direction in which the orifice flow path extends, and further includes a plurality of control pins arranged to be spaced apart from the heat transfer tube flow path. The above bellows tube is, Reciprocating the orifice toward the heat transfer tube so that the flow rate of the water supply can be varied as the spacing between the above-mentioned control pin and the above-mentioned heat transfer tube increases or decreases, Steam generator.

10. In Paragraph 1, The above orifice has a shape that protrudes in the direction in which the orifice flow path extends, and further includes a plurality of control pins arranged to be spaced apart from the heat transfer tube flow path. The orifice has one surface facing the heat transfer tube passage and another surface opposite to the one surface on which the bellows tube is disposed. The above bellows tube is, Reciprocating the orifice toward the heat transfer tube so that the flow rate of the water supply can be varied as the spacing between the above-mentioned control pin and the above-mentioned heat transfer tube increases or decreases, Steam generator.

11. In Paragraph 1, The above orifice is, orifice body; and It includes a plurality of fluid pin portions that reciprocate in the direction in which the above orifice path extends, The above bellows tube is, A structure disposed between the orifice body and the fluid pin portion, which reciprocates the fluid pin portion in the direction in which the orifice flow path extends. Steam generator.

12. In Paragraph 1, The above plurality of heat transfer tubes are, It includes a first heat transfer channel having a predetermined length, a second heat transfer channel having a length longer than the first heat transfer channel, and a third heat transfer channel having a length longer than the second heat transfer channel. When the plurality of orifice passages are selectively connected to the plurality of heat transfer tube passages, they are arranged such that the cross-sectional area communicating with the plurality of heat transfer tube passages is different for each of them. Steam generator.

13. In Paragraph 1, The above driving means further includes a driving auxiliary means that pressurizes the orifice in a direction opposite to the direction in which the driving means moves the orifice, and The above orifice is disposed between the driving means and the driving auxiliary means. steam generator 14. In Paragraph 1, The above driving assist means is formed as a corrugated tube in a near-vacuum state. Steam generator.

15. In Paragraph 1, The above driving assist means includes a corrugated tube in a near-vacuum state, Steam generator.

16. In Paragraph 1, A spring having elasticity or a corrugated tube containing a spring inside, Steam generator.

17. Reactor vessel containing coolant; A core that causes nuclear fission inside the above reactor vessel; and It includes a steam generator that generates steam through heat exchange of the above-mentioned coolant; The above steam generator is, Case through which the reactor coolant passes; A heat transfer tube comprising a plurality of heat transfer tube passages through which the water supply travels; A water supply header connected to the above heat transfer tube and for supplying the above water; A steam header in which the feedwater supplied from the above feedwater header undergoes a phase change into main steam and is discharged; An orifice comprising a plurality of orifice passages disposed inside the above-mentioned water supply header and communicating with the above-mentioned heat transfer tube passage, and To regulate the pressure of the water supply flowing into the heat transfer tube, it includes a driving means for moving the position of the orifice relative to the heat transfer tube; The above driving means is, A bellows tube that expands or contracts to allow the orifice to move, and a compressible fluid filled inside to allow the bellows tube to expand or contract, nuclear pile.

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